/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/* vim: set ts=8 sts=4 et sw=4 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef DecomposeIntoNoRepeatTriangles_h_

#define DecomposeIntoNoRepeatTriangles_h_

#include "GLTypes.h"

#include "nsRect.h"

#include "nsTArray.h"

namespace mozilla {

namespace gl {

/** Helper for DecomposeIntoNoRepeatTriangles

  */

class RectTriangles {

public:

    typedef struct { GLfloat x,y; } coord;

    // Always pass texture coordinates upright. If you want to flip the

    // texture coordinates emitted to the tex_coords array, set flip_y to

    // true.

    void addRect(GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1,

                 GLfloat tx0, GLfloat ty0, GLfloat tx1, GLfloat ty1,

                 bool flip_y = false);

    /**

      * these return a float pointer to the start of each array respectively.

      * Use it for glVertexAttribPointer calls.

      * We can return nullptr if we choose to use Vertex Buffer Objects here.

      */

    InfallibleTArray<coord>& vertCoords() {

        return mVertexCoords;

    }

    InfallibleTArray<coord>& texCoords() {

        return mTexCoords;

    }

    unsigned int elements() {

        return mVertexCoords.Length();

    }

private:

    // Reserve inline storage for one quad (2 triangles, 3 coords).

    AutoTArray<coord, 6> mVertexCoords;

    AutoTArray<coord, 6> mTexCoords;

    static void

    AppendRectToCoordArray(InfallibleTArray<coord>& array, GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1);

};

/**

  * Decompose drawing the possibly-wrapped aTexCoordRect rectangle

  * of a texture of aTexSize into one or more rectangles (represented

  * as 2 triangles) and associated tex coordinates, such that

  * we don't have to use the REPEAT wrap mode. If aFlipY is true, the

  * texture coordinates will be specified vertically flipped.

  *

  * The resulting triangle vertex coordinates will be in the space of

  * (0.0, 0.0) to (1.0, 1.0) -- transform the coordinates appropriately

  * if you need a different space.

  *

  * The resulting vertex coordinates should be drawn using GL_TRIANGLES,

  * and rects.numRects * 3 * 6

  */

void DecomposeIntoNoRepeatTriangles(const gfx::IntRect& aTexCoordRect,

                                    const gfx::IntSize& aTexSize,

                                    RectTriangles& aRects,

                                    bool aFlipY = false);

} // namespace gl

} // namespace mozilla

#endif // DecomposeIntoNoRepeatTriangles_h_